The present invention relates to a carriage assembly for lift trucks and more particularly to a load supporting fork configuration selected for handling angularly shaped loads or objects which may be formed from friable or other materials subject to damage during handling.
Load supporting forks for lift trucks and the like are generally formed in an L-shaped configuration from rectangular bar stock, the L-shaped forks being adapted for mounting upon a lift truck carriage, for example. Such forks commonly include a vertical leg attachable to the carriage and a forwardly extending, horizontal leg intended to pass under or penetrate an opening in a load. It is further common in the design of lift trucks to provide means for tilting the carriage so that the forwardly projecting tips are raised in order to assure that the load is maintained upon the forks during handling. When the carriage is tilted in this manner, the load tends to be shifted rearwardly into abutting engagement with the vertical leg of each fork while also resting upon an upper surface of its forwardly extending leg.
A problem has been encountered in connection with the use of such load supporting forks, particularly when they are employed to move or handle loads subject to damage. A particular example of such a load may comprise concrete blocks which are commonly moved in stacks by lift trucks. The concrete blocks are formed with openings extending therethrough, the forks being laterally movable upon the carriage for alignment with these openings in order to thus engage and support an entire stack of blocks.
When used in this manner, conventional load supporting forks have been found capable of causing damage in at least two ways. Initially, the forwardly extending tips of conventional forks are normally shaped to have elongated laterally extending edges formed by the intersection of a tapered bottom surface of the fork and a top surface of the fork. The side surfaces of the fork may have little or no taper so that the sharp edge extends almost entirely across the lateral dimension of each fork. When the forks are engaged with the concrete blocks, the forks do not always align perfectly with the openings in the blocks so that these leading edges of the forks tend to break or chip away the friable concrete material of the blocks.
In addition, when a large stack of concrete blocks is arranged upon the load supporting forks of a lift truck carriage, certain blocks in the load tend to support a substantial portion of the load against intersecting surfaces of the vertical and forward legs of the fork. Within the prior art, this intersection of the forks has commonly been formed with a large radius fillet, commonly of concave configuration. Thus, the fillet extends outwardly from or blocks the intersection between the load supporting surfaces of the fork and tends to break or chip away friable material from the concrete block during loading and handling.